Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The nacelle includes a rotor assembly coupled to the gearbox and to the generator. The rotor assembly and the gearbox are mounted on a bedplate support frame located within the nacelle. In many wind turbines, the gearbox is mounted to the bedplate via one or more torque supports or arms. The rotor blades capture kinetic energy of wind using known airfoil principles and transmit the kinetic energy in the form of rotational energy so as to turn a main shaft coupling the rotor blades to the gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
More specifically, the majority of commercially available wind turbines utilize multi-stage geared drivetrains to connect the turbine blades to an electrical generator. The wind turns the turbine blades, which spin a low speed shaft, i.e. the main shaft. The main shaft is coupled to an input shaft of a gearbox, which has a higher speed output shaft connected to a generator. Thus, the geared drivetrain aims to increase the velocity of the mechanical motion. Further, the gearbox and the generator are typically supported by one or more bearings and mounted to the bedplate via one or more torque arms or supports.
Over time, the main shaft and associated bearings may become worn and/or damaged due to loads and forces from the wind acting on the wind turbine components. Unfortunately, repair of the main shaft and/or the main bearing assembly often requires the turbine head (machine head) to be removed from atop the nacelle and transported to a factory wherein the bedplate is stood up vertically to remove the main shaft and bearing assembly, which is a very time-consuming and expensive procedure.
U.S. Pat. No. 8,696,302 discloses a method for repairing or replacing a main bearing on a wind turbine without removing the rotor and main shaft. This method is not suited for wind turbine designs wherein bearing replacement or repair requires removal of the rotor and main shaft.
U.S. Pat. No. 8,108,997 discloses a method for stabilizing the main shaft within the bedplate on a single bearing unit to repair or replace the gear box. This method is not suited for a procedure that requires removal of the rotor and main shaft to replace or repair the main bearing assembly.
To date, there has been no viable method for repairing, replacing, or upgrading a dual main bearing unit seated in a bedplate in the field, wherein the procedure may or may not require removal of the rotor and main shaft from the bedplate.
Thus, the industry is in need of new and improved systems and methods for repairing, replacing, or upgrading a main shaft bearing seated in the bedplate of the wind turbine in the field, wherein the bedplate remains installed in a horizontal position atop the tower, or is removed from the tower in the field.